Fifth Dallas officer dies (VIDEO)

Ting Shen/The Dallas Morning News via AP

A Dallas Area Rapid Transit police officer receives comfort at the Baylor University Hospital emergency room entrance Thursday, July 7, 2016, in Dallas. Police say one rapid-transit officer has been killed and three injured when gunfire erupted during a protest in downtown Dallas over recent fatal shootings by police in Louisiana and Minnesota.

Police announced the fifth officer's death early Friday morning. It wasn't immediately clear which department that officer belonged to.

UPDATE 11:10 p.m.:

Maria R. Olivas/The Dallas Morning News via AP

Dallas police respond after shots were fired during a protest over recent fatal shootings by police in Louisiana and Minnesota, Thursday, July 7, 2016, in Dallas. Snipers opened fire on police officers during protests; several officers were killed, police said.

Three people are in custody and a fourth suspect was exchanging gunfire with authorities, Dallas Police Chief David Brown said early Friday morning.

The suspect is not cooperating and has told negotiators he intends to hurt more law enforcement officials, the chief said.

The gunfire broke out around 8:45 p.m. Thursday while hundreds of people were gathered to protest fatal police shootings this week in Baton Rouge, Louisiana, and suburban St. Paul, Minnesota.

Protests were also held in several other cities across the country Thursday night after a Minnesota officer on Wednesday fatally shot Philando Castile while he was in a car with a woman and a child. The aftermath of the shooting was livestreamed in a widely shared Facebook video. A day earlier, Alton Sterling was shot in Louisiana after being pinned to the pavement by two white officers. That, too, was captured on a cellphone video.

Video footage from the Dallas scene showed protesters were marching along a street in downtown, about half a mile from City Hall, when the shots erupted and the crowd scattered, seeking cover.

Brown said that it appeared the shooters "planned to injure and kill as many officers as they could."

The search for the shooters stretched throughout downtown, an area of hotels, restaurants, businesses and some residential apartments. The scene was chaotic, with helicopters hovering overhead and officers with automatic rifles on the street corners.

"Everyone just started running," Devante Odom, 21, told The Dallas Morning News. "We lost touch with two of our friends just trying to get out of there."

One woman was taken into custody in the same parking garage where the standoff was ongoing, Brown said. Two others were taken into custody during a traffic stop.

Brown said police don't have a motivation for the attacks or any information on the suspects. He said they "triangulated" in the downtown area where the protesters were marching and had "some knowledge of the route" they would take. He said authorities have not determined whether any protesters were involved with or were complicit in the attack.

Police were not certain early Friday that all suspects have been located, Brown said.

Demonstrator Brittaney Peete told The Associated Press that she didn't hear the gunshots, but she "saw people rushing back toward me saying there was an active shooter."

Peete said she saw a woman trip and nearly get trampled.

Late Thursday, Dallas police in uniform and in plainclothes were standing behind a police line at the entrance to the emergency room at Baylor Medical Center in Dallas. It was unclear how many injured officers were taken there. The hospital spokeswoman, Julie Smith, had no immediate comment.

Three of the officers who were killed were with the Dallas Police Department. One was a Dallas Area Rapid Transit officer.

Texas Gov. Greg Abbott released a statement saying he has directed the Texas Department of Public Safety director to offer "whatever assistance the City of Dallas needs at this time."

"In times like this we must remember — and emphasize — the importance of uniting as Americans," Abbott said.

UPDATE:

DALLAS - Dallas police say four officers have died after at least two snipers opened fire during protests downtown. Seven other officers were wounded.

Video

Dallas police shooting

Police Chief David O. Brown said police have a suspect cornered in a garage and are negotiating with that person. He says the snipers fired upon officers "ambush style."

Brown had said three officers were killed, and police issued a tweet later saying a fourth officer had died.

Brown says snipers shot from "elevated positions" during a protest over two recent fatal police shootings.

The gunfire broke out around 8:45 p.m. Thursday. Live TV video showed protesters marching along a street in downtown when the shots erupted and the crowd scattered, seeking cover.

DALLAS — Two snipers apparently shot 10 police officers during protests in Dallas on Thursday night and three officers are dead, the city's police chief said in a statement.

A statement from Dallas Police Chief David Brown released by a city spokeswoman said "it appears that two snipers shot ten police officers from elevated positions during the protest/rally."

The gunfire broke out around 8:45 p.m. Thursday while hundreds of people were gathered to protest fatal police shootings this week in Baton Rouge, Louisiana, and suburban St. Paul, Minnesota.

The statement said three officers are deceased, two are in surgery and three are in critical condition.

"An intensive search" for suspects is currently underway, it said. No one is in custody.

Live TV video showed protesters marching along a street in downtown, about half a mile from City Hall, when the shots erupted and the crowd scattered, seeking cover.

Scores of police and security officers were on hand. Police and others hunched behind cars outside a parking garage. Officers with guns drawn were running near and into the parking garage as police searched for the shooter.

TV cameras showed the search for the gunman stretched throughout downtown, an area of hotels, restaurants, businesses and some residential apartments. The scene was chaotic, with helicopters hovering overhead and officers with automatic rifles on the street corners.

Associated Press writer Ezra Kaplan in New York contributed to this report.